Final Foundation Treatment at Hoover Dam

In the design of Hoover Dam, the Bureau of Reclamation (USBR) of the United States Department of the Interior found it necessary to give careful consideration to certain features that were not subject to an exact mathematical analysis. The treatment of the foundation was one of those matters that involved a design based largely on experience and precedent. Because of the height of the structure and the resulting increase in pressure caused by the exceedingly high head, there was no established antecedent that would furnish a suitable comparison for the foundation treatment. However, pressure grouting was anticipated to reduce seepage, to eliminate uplift pressure in the foundation beneath the dam and appurtenant structures, and to correct defects in the bedrock. In addition to the grouting treatment, a drainage system downstream from the grouted area was considered essential.